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Forum Index : Electronics : Anemometer for solar panel protection
| Author | Message | ||||
| Shelly Newbie  Joined: 22/12/2009 Location: SpainPosts: 25 |
Hi, Has anyone used an anemometer output to return solar panels to the horizontal in strong winds? I live in an area where we can get sudden squalls with winds of 60/70 km/hr and the occasional tropical storm. I would like to find a method that should the wind go above a certain speed the panels are moved to the horizontal to reduce possible damage to the panels and framework. I know systems exist but as yet haven't found a DIY nor commercial system. Thanks. |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Shelly I know the problem with the wind you mention, and have seen some attempts to do just that to protect the array, but the nature of the gusts was such that the damage was done before the panels where parked, a system I played with but never fully developed was a cable system connected to the extremity of the array through an equalizer pulley system to anchor points on the ground, the cable went through a spring loaded cable brake that was activated by a wind vane that swiveled and the horizontal vane lifted in high wind triggering a reed switch that fired the brake and locked it on and at the same time disconnected the tracker drive, you had to do a manual reset and unlock the brake. In the end I found it was easier to make the tracker frame stronger to withstand the stress, and I also put a 150 mm spoiler across the top of the panels to reduce lift. All the best Bob Foolin Around |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Bob is 100% correct, Make it strong to handle the winds you get. Most trackers work on high reduction gear boxes to give slow controlled movement to the panels, and to expect the same drive to react fast enough for changing wind conditions is just asking for trouble. Very simply if that is what the system relys on to protect it, it will get distroyed. With the average angle the panels have on a tracker it will create a steep ramp for the air flow to glide over and not be so forcefull as a flat wall. The winds that do damage are the swirling winds and no matter where you face the panels it wont help greatly. Drag the fan out of the cupboard and a sheet of cardboard and do some model testing of air flow and angles, you will more than likely fine as we did, face on to the wind is proberly safer than side on, as the positive pressure is applied evenly where with side on it tends to yaw the panels some. Either way engineer the problem out rather than trying to go light and fragile with expecting some sensing system to save the day. It wont!! Pete. Sometimes it just works |
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| Shelly Newbie Joined: 22/12/2009 Location: SpainPosts: 25 |
Hi folks, Thanks for the advice. I was hoping to buy some second hand panels but the seller has disappeared, so I'm going to have to modify what I've got, hence the interest in trackers. I live off grid. A group of neighbours were quoted 17,000€ each to supply electricity to the meter. More to connect to the house. A little expensive! I have 1,200 watts of panels. 6 panels are mounted in a very strong mounting which I'll turn through a right angle and mount a la Traxel, the other 4 I'll have to make a similar frame. Photos when it's completed. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Shelly Keep us in the loop with your tracker, bur remember strong is best All the best Bob Foolin Around |
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Loomberah Regular Member  Joined: 11/06/2008 Location: AustraliaPosts: 43 |
I use a simple wind switch to slew my equatorial tracker horizontal when the wind gets to about 40km/hr, well below the speed where problems might occur. That way I dont get caught out when it jumps from 40 to 80km/hr. My 2.19kW array of 12 panels is going to present a much smaller cross section to the wind when side on rather than face on, so the stresses on the mount will be much less when it is parked. It parks in that position overnight too. Slewing to the wind park position takes less than a minute from fully E or W, and much less during the middle of the day, when the strongest winds, associated with thunderstorms, are likely to occur. I'm also building a new alt-azimuth mount to take ~2kW of panels and it will have an anemometer that senses wind speed, rather than the wind switch, which very occasionally gets triggered by birds sitting on it. Loomberah weather +solar&UV, astronomy, photography, organic farm |
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| Shelly Newbie Joined: 22/12/2009 Location: SpainPosts: 25 |
Could you post some photos or a diagram. I'm still in the planning stage and am going to convert a static frame to single axis and build a couple more small trackers, possibly 2 axis but that will depend on the design I come up with. I'm also buying some solar cells to make my own panels. At the end I'll have approx 2 kw of panels and then I'll have to find more batteries to store the extra energy and so it goes on. I retire next year, everything must be finished by then. |
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| Loomberah Regular Member Joined: 11/06/2008 Location: AustraliaPosts: 43 |
I'm at work at the moment, but the switch on the 12 panel tracker is just an Aluminium ring with a spring mounted brass tube up through the middle of it and a length of dowel inserted into the top of it to catch the wind. When they make contact it closes the circuit. It has to stay connected for a couple of seconds to trigger the parking, which happens around 40km/hr. Vary the length of the dowel to vary the activation speed. Winds that strong are quite rare at home, so wind parking is only a very ocsasional loss of a little power. The new tracker will use an anemometer, once the pulses reach a certain count per second, it will trigger the parking. Have a look here for Dave's trackers and wind parking sensors etc Wind parking etc Loomberah weather +solar&UV, astronomy, photography, organic farm |
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